If you do a lot of copying and pasting, the Scribbler widget's a godsend. Scribbler displays a history of configurable length of all the text and URLs you've copied to clipboard over time, even after you've shut down your computer. Scribbler will check for duplicates and make URLs and file paths clickable. The downside is Scribbler only handles text, so images copied to clipboard will not appear. Scribbler is a free download and works with Yahoo! Widget Engine for Mac or Windows.